If you use an @notification in chat messages it will notify the corresponding user with a small circle (or snowman) on their gravatar and (if enabled) a sound effect.
Now, when you have notified a user that way they will be notified again if you edit the message containing the @notification. I don't think this behaviour is optimal. In most cases I don't really want to ping the user again; I just want to correct some small typo.
I suggest to change the behaviour to not repeat the ping when posts are edited.